For mobile terminals such as mobile phones or tablet computers, words are inputted using an input method performed on a touch panel. Usually, when English letters are inputted using the input method at a full keyboard interface, it is necessary to switch the case of each to-be-inputted letter according to the practical need. For conventional input methods, the case of the letter is mainly switched in the following two modes.
In a first mode, whether an uppercase format is to be adopted to input the letter is selected in accordance with the Shift key. When the Shift key has been selected, an uppercase letter is to be inputted, and otherwise, a lowercase letter is to be inputted.
In a second mode, when inputting the letter, whether the uppercase or lowercase letter is to be inputted is determined through a rapid clicking operation or a pressing and holding operation. When a keyboard is clicked rapidly, the lowercase letter is to be inputted, and when the keyboard is pressed and held, the uppercase letter is to be inputted.
However, in the first mode, it is necessary to select the Shift key before inputting the uppercase letters, i.e., an additional operation needs to be performed as compared with a situation where the lowercase letters are inputted, resulting in a time-consuming, complex and less-efficient operation. In the second mode, it is necessary to press and hold the keyboard when inputting the uppercase letters, resulting in a time-consuming and less-efficient operation as compared with a situation where the lowercase letters are inputted through rapid clicking.
In a word, for the conventional character input methods, there are such problems as being time-consuming, complex and less-efficient when some characters are inputted.